Deflectable sheath catheters

ABSTRACT

The present invention provides devices and methods for the treatment of atrial fibrillation. In one embodiment a deflectable sheath catheter includes an elongate catheter body having proximal and distal ends, the distal end having a distal tip region that includes a plurality of flexible segments with varying degrees of stiffness. A handle portion can be located at the proximal end of the catheter body to provide a steering mechanism that causes the distal tip region to deflect according to a compound curve.

CROSS-REFERENCE TO RELATED APPLICATIONS

The pending application is a continuation-in-part of U.S. patentapplication Ser. No. 10/357,156, filed Feb. 3, 2003, which is acontinuation-in-part of U.S. patent application Ser. No. 09/924,393,filed Aug. 7, 2001.

The pending application is also a continuation-in-part of U.S. patentapplication Ser. No. 10/674,114, filed Sep. 29, 2003, which is acontinuation of U.S. patent application Ser. No. 09/616,275, filed Jul.14, 2000, now U.S. Pat. No. 6,626,900 (issued Sep. 30, 2003), which is acontinuation-in-part of U.S. patent application Ser. No. 09/602,420,filed Jun. 23, 2000, now U.S. Pat. No. 6,572,609 (issued Jun. 3, 2003),which is a continuation-in-part of U.S. patent application Ser. No.09/357,355, filed Jul. 14, 1999, now U.S. Pat. No. 6,423,055 (issuedJul. 22, 2002).

The pending application is also a continuation-in-part of U.S. patentapplication Ser. No. 10/865,558, filed Jun. 10, 2004, which claimspriority to U.S. Provisional Application Ser. No. 60/477,374, filed Jun.10, 2003.

FIELD OF THE INVENTION

The present invention generally relates to methods and devices fortreating atrial fibrillation, and in particular to deflectable guidecatheters which are used to provide access and delivery of ablationinstruments, medications, or fluids into the heart.

BACKGROUND OF THE INVENTION

Cardiac arrhythmias, such as atrial fibrillation, are irregularities inthe normal beating pattern of the heart and can originate in either theatria or the ventricles. Atrial fibrillation is characterized by rapidrandomized contractions of the atrial myocardium, causing an irregular,often-rapid ventricular rate, and can give rise to other forms ofcardiovascular disease, including congestive heart failure, rheumaticheart disease, coronary artery disease, left ventricular hypertrophy,cardiomyopathy or hypertension.

Treatments for atrial fibrillation have focused on the pulmonary veins,which have been identified as one of the origins of errant electricalsignals responsible for activating atrial fibrillation. In one knownapproach, tissue is ablated in a circumferential pattern at locationssuch as the within the pulmonary veins, at the ostia of the pulmonaryveins, or surrounding the pulmonary veins. By ablating the heart tissueat these locations, the electrical conductivity from one segment toanother can be blocked such that the resulting segments become too smallto sustain the fibrillatory process on their own.

In order to reach locations within or surrounding the heart, guidecatheters are commonly used. Most guide catheters have proximal anddistal ends connected by a long, tubular body having one or more lumensformed therein. The proximal end of the catheter usually includes ahandle for control of the catheter by the operator and various ports forintroduction of fluids and instruments through the catheter lumen, andthe distal end includes a tip which is inserted into the patient. Forexample, in vascular applications, the tip of the catheter can beinserted into a major vein, artery, or other body cavity. The catheteris then further inserted and guided to the area of concern. Moreover,the catheter can also function as a “sheath” or “guide catheter” in thatit can be used a delivery conduit for other tools, such as balloonsand/or stents for performing angioplasty or other instruments mappingelectrodes and ablation devices for conducting procedures within theheart.

Current methods for inserting and guiding a catheter include the use ofa guide wire where the guide wire is fed into position within thepatient and then the catheter is passed over the guide wire. However,one drawback associated with this method, when the target ablation sitesare in or near the pulmonary veins on the posterior surface of theheart, is that it is often difficult, if not impossible, to advance theguide wire all the way to the ultimate target site due to the shape ofthe heart muscle.

Alternatively, a steerable catheter can be used. Steerable cathetersrequire an ability to selectively deflect the distal tip of the catheterin a desired direction by permitting an operator to adjust the directionof advancement of the distal end of the catheter, as well as to positionthe distal portion of the catheter. The deflection of the distal tip istypically provided by one or more pull wires that are attached at thedistal end of the catheter and extend to a control handle such that thesurgeon can selectively deflect the tip and/or rotate the catheter shaftto navigate into the correct position.

When designing such steerable catheters for access into the heart, it isimportant to have sufficient flexibility in the catheter shaft so thatwhen the catheter is advanced through a blood vessel or heart chamber itcan follow the inherent curvature of the biological structures withoutpuncturing them. However, achieving a balance between the “pushability”of the catheter (that is, the ability to direct the tip of the catheterto the target location without buckling or kinking) and the necessarystiffness to allow the catheter to access the heart, especially whennavigating the sharp turns necessary to access locations in the leftatrium of the heart, can be difficult.

Prior art deflectable catheters typically have a single stiffness value,or at best, one stiffness value for the catheter body and one stiffnessvalue for the deflectable tip. As a result, these catheters oftenrequire large spatial volumes in which to bend and are unable to maketight turns that are sometimes necessary to reach a target regionwithout causing trauma to a patient. Particularly, access to the leftatrium for the treatment of atrial fibrillation is particularlydifficult when the ultimate target region is in the vicinity of theright inferior pulmonary vein, as this vein is usually the closest tothe transseptal puncture, requiring the catheter to turn 180° indirection in order to achieve proper orientation.

Currently methods to address this issue include using a set of sheathcatheters with different curves and removing one catheter and replacingit with another, several times. However, this exchange is time consumingand can present additional risks, such as accidental entrainment of airembolisms.

More difficulties arise when the catheter includes an ablationinstrument having a balloon, as additional maneuvering can be requiredto properly orient the balloon within or at the mouth of the vein.Further, axial force may be required in order to occlude the pulmonaryvein at the ostium and the lack of stiffness of most catheters rendersthe application of sufficient force to successfully seal the vein priorto ablation problematic.

Accordingly, there exists a need for deflectable sheath catheters thatcan navigate and access narrow and limited spaces leading into, andwithin the heart, especially the left atrium. There also exists a needfor improved methods of treating atrial fibrillation that provide betterand/or more precise location of ablation instruments within the heart.

SUMMARY OF THE INVENTION

Devices and methods are disclosed herein for use in diagnostic purposes,such as delivering an imaging agent or for therapeutic purposes such asfor delivering various ablation instruments or mapping instruments toregions of the heart, such as to the left atrium, left atrial appendage,or the pulmonary veins.

In one aspect, the deflectable sheath catheters include a deflectabletip section at a distal end and having a varying stiffness along atleast a portion of the distal tip section which allows the deflectabletip to deflect along a compound curve. As a result of this tip, thepresent invention permits ready access to all four pulmonary veins ofthe left atrium via a single transseptal approach, especially the rightinferior pulmonary vein. Moreover, this access is achieved withoutprolapsing and in a manner that also permits the application of axialforce, such that an ablation instrument inserted through the sheathcatheter can be both maneuvered into place and held in position duringablation. This is especially useful when the ablation instrumentincludes a balloon element that must be urged against the ostium of avein in order to occlude it.

In another aspect, the present invention can include a deflectablesheath catheter having an elongate catheter body with proximal anddistal ends, the catheter body comprising multiple flexible segmentsalong its length such at least one (and preferably two or more) of theflexible segments has a different stiffness. The segments of differentstiffness are preferably formed by a plurality of polymeric segments ofthe elongate body having different durometers, and in one embodiment,the durometer of the distal section decreases in the distal directionalong at least a portion of the section. The catheter can furtherinclude a handle portion at its proximal end, and a deflectable tipsection at its distal end wherein the deflectable tip section isdeflectable along a compound curve or a spiral curve. While the handlecan have a variety of configurations, in one embodiment, it includes ahemostasis valve.

Another aspect of the present invention can include a deflectable sheathcatheter having an elongate catheter body with proximal and distal endssuch that the catheter body has at least two segments along its length,with at least one segment having a different stiffness. In otherembodiments, the catheter can have three, four, five, etc. wallsegments. The catheter can further include a stiffening element (e.g., adilator) which is initially deployed within the catheter body to assistin passing the catheter to the target region. The stiffening element ordilator can subsequently be removed or partially retracted. Moreover,the catheter can include a handle portion at its proximal end, and adeflectable tip section at its distal end wherein the deflectable tipsection is deflectable along a compound curve or a spiral curve as aresult of the segments of different stiffness.

In another embodiment, the catheter can include at least one braidedwire reinforcement layer, where the layer can surround at least aportion of the body length. The layer can be continuous, oralternatively, discontinuous. Moreover, the layer can be varied toprovide segments of different stiffness.

In another embodiment, the catheter can further include an actuator thateffects deflection of the deflectable tip section. While the actuatorcan have a variety of configurations, the actuator can further include alock to fix the deflectable distal end section in a particular curvewithin its range of movement. Alternatively the actuator can include apull wire mechanically linking the deflectable distal end section to aproximal handle portion.

In another aspect of the invention, the deflectable tip section of thesheath catheter can be pre-bent, e.g., out of the plane of deflection,such that the operator can deflect the tip section in one plane whilethe tip itself is oriented in a non-planar direction. The bend can beformed during manufacturing or the tip can be malleable to permit theuser to select a desired bend angle and/or orientation prior to use. Thebent tip can be formed at an angle ranging from about 5° to about 90°relative to a central axis of the catheter body in an unflexed state,preferably at an angle ranging from about 10° to about 60° relative tothe central axis, and, more preferably in certain applications, at anangle ranging from about 15° to about 45° relative to the central axisof the catheter body.

In a further aspect of the invention, deflectable sheath catheters aredisclosed with irrigation holes placed at the distal end of adeflectable tip section. The holes can allow for additional irrigationand fluidic communication between a central lumen in the elongatecatheter body and the human vasculature. There is preferably at leastone irrigation hole included at the tip section, but the number of holescan be varied depending on the design configuration. In an exemplaryembodiment, irrigation side holes can allow for passage of fluidsthrough the deflectable sheath catheter when the distal end of thecatheter is in direct contact with the endocardium and a distal tip holewould be occluded.

In another aspect, a deflectable sheath catheter can be adapted fordisposition within a heart and includes at least one cardiac ablationinstrument which can be deployed through the deflectable sheath catheterto a desired target location. The ablation instrument can furtherinclude an optional anchorage element, such as an anchoring balloon, tocontact a cardiac structure and secure the device in place.

In one embodiment, the ablation instrument includes a radiant energydelivery element movable within the lumen of a deflectable sheathcatheter such that it can be disposed at the desired location anddeliver radiant energy through a transmissive region of the instrumentto a target tissue site. The ablation instrument can also optionallyinclude a projection balloon that can be employed, alone or togetherwith fluid releasing mechanisms, to provide a blood-free transmissionpathway from the energy emitter to the tissue target.

In another embodiment, the ablation instrument includes an ultrasoundenergy delivery element movable within the lumen of a deflectable sheathcatheter such that it can be disposed at the desired location anddeliver radiant ultrasound energy through a transmissive region of theinstrument to a target tissue site. The ablation instrument can alsooptionally include a projection balloon and/or a focusing element toreflect the energy emitter to the tissue target.

In another embodiment, the ablation instrument includes microwave energydelivery element movable within the lumen of a deflectable sheathcatheter such that it can be disposed at the desired location anddeliver radiant microwave energy through a transmissive region of theinstrument to a target tissue site. The ablation instrument can alsooptionally include a projection balloon to provide a focusing element toreflect the energy emitter to the tissue target.

In another embodiment, the ablation instrument includes a cryoablationenergy delivery element movable within the lumen of a deflectable sheathcatheter such that it can be disposed at the desired location to atarget tissue site with a cryogenic surface. The ablation instrument canalso optionally include a projection balloon to clear blood from theablation site and allow delivery of cryoablation of the tissue target.Alternatively, the catheter can include an ablation instrument todeliver ablative fluids, electrical resistive heating or other ablationmodalities.

In another aspect, a cardiac ablation assembly is provided that includesa deflectable sheath catheter adapted for disposition within a hearthaving at least one lumen therein, the catheter having at least onesegment of different stiffness to form a compound curve upon deploymentand deflection within the heart, and an ablation instrument movablewithin a lumen of the deflectable sheath catheter such that it can bedisposed at a target tissue site to deliver ablative energy. In oneembodiment, the ablation instrument can be a radiant energy emitterfurther comprising a translatory mechanism for positioning the emitterat a selected location within the deflectable sheath catheter. Moreover,the radiant energy emitter can be an ultrasound emitter, hypersoundemitter, light emitter, microwave radiation emitter, radio-frequency(RF) radiation emitter, x-ray radiation emitter, ionizing radiationemitter, or a particle beam radiation emitter, depending upon theparticular application. In another embodiment, the ablation instrumentcan be a contact ablation instrument, such as a cryogenic ablationinstrument, ablative fluid instruments, or a heating instrument.

In another aspect, a method is provided for cardiac access. The methodincludes inserting a guide wire into a patient to a target region andthen using a guidewire to deliver a deflectable sheath catheter having adeflectable tip into a target region. The method further includespassing the sheath catheter (which can also include an optional internalstiffening element or “dilator”) over the guide wire such that thecatheter can be directed to the target region. Following removal of theguide wire and dilator, the deflectable tip section of the sheathcatheter can be bent, preferably into a compound or a spiral curve, inorder to access one or more target regions within the left atrium of theheart. Finally, the tip section can be locked in a bent position, and amedical instrument or treatment fluid is delivered through the catheterto a target site within the heart.

In another method according to the invention, a guide wire is firstinserted into the femoral vein and advanced through the inferior venacava into the right atrium and, optionally, into the left atrium via anatrial septal puncture, where it can be further advanced until it entersa pulmonary vein. A dilator is then positioned within the deflectablesheath catheter and both, together, are positioned over the guide wireand advanced into the heart. If the transseptal puncture has not beenperformed with the guidewire, the deflectable sheath catheter(preferably with the stiffening element disposed therein) can be used toperform the puncture. The sheath catheter is then advanced intoproximity of the target site, e.g., the mouth of a pulmonary vein. Theguide wire (and dilator) are then removed and replaced with an ablativeinstrument, which is positioned by advancing the instrument to contactthe ostium of the pulmonary vein with sufficient axial force to create aseal and deliver ablative energy to the target tissue region to ablatetissue and form a conductive block.

In another aspect, a method includes positioning a sheath catheterhaving a deflectable distal end segment in the left atrium of a heart,orienting said sheath catheter such that an ablation instrument can bedelivered through the sheath catheter to a position proximal to a firstpulmonary vein, activating the ablation instrument to form acircumferential lesion around the first pulmonary vein, repositioningthe sheath catheter by deflecting the distal end segment to anotherorientation, and activating the ablation instrument to form acircumferential lesion around at least one additional pulmonary vein. Inone embodiment, the method further includes repeating the steps oforienting the sheath catheter and activating the ablation instrumentuntil all of the pulmonary veins are isolated by circumferentiallesions. In another embodiment, the method further includes positioning(or, alternatively, repositioning) the sheath catheter fluoroscopically,as well as initially deploying the sheath catheter (or the sheathcatheter together with a stiffening inner dilator) in the heart over aguide wire. Moreover, the method includes using a sheath cathetertogether with the stiffening inner dilator to create a septal puncturein order to gain access to the left atrium of the heart.

In another embodiment, the step of activating the ablation instrumentfurther includes positioning a radiant energy emitter at a selectedlocation within a balloon catheter that is deployed within the heart viathe sheath catheter and then activating the radiant energy emitter. Theradiant energy emitter can be a variety of energy emitters, such as anultrasound emitter, a hypersound emitter, a light emitter, a microwaveradiation emitter, a radio-frequency (RF) radiation emitter, an x-rayradiation emitter, an ionizing radiation emitter, and particle beamradiation emitter.

In one embodiment, the step of activating the radiant energy emitterfurther includes activating a light emitting element to expose thetarget region to light energy to induce photocoagulation of cardiactissue within the target region. Alternatively, the step of activatingthe radiant energy emitter can include activating a light emittingelement to expose the target region to light energy to induce acontinuous lesion in the cardiac tissue, activating a light emittingelement having a beam-forming optical waveguide to expose the targetregion to an annular beam of light energy to induce a circumferentiallesion in cardiac tissue, and/or activating a light emitting elementgenerating photoablative radiation at a desired wavelength ranging fromabout 800 nm to about 1000 nm, or from about 915 nm to about 980 μm.

Moreover, the step of activating the radiant energy emitter can furthercomprise activating an ultrasound emitting element to expose the targetregion to acoustic energy to induce photocoagulation of cardiac tissuewithin the target region, or, alternatively, activating a radiationemitting element to expose the target region to at least one form ofradiant energy selected from the group consisting of microwave, x-ray,gamma-ray and ionizing radiation to induce photocoagulation of cardiactissue within the target region.

In another embodiment, the method further includes inflating aprojection balloon to clear blood from a transmission pathway betweenthe energy emitter and a target region of cardiac tissue, anddetermining whether a clear transmission path has been establishedbetween the radiant energy emitter and the target tissue based onreflectance measurements by an optical sensor disposed within the lumenof the deflectable sheath catheter. Alternatively, the method furtherincludes measuring at least two different wavelengths of reflected lightcollected by the optical sensor to determine whether a projection pathexists.

In another embodiment, the step of activating the ablation instrumentfurther includes deploying a contact ablation instrument within theheart via the sheath catheter, positioning the contact ablationinstrument at a selected location and then activating the contactablation instrument. While the contact ablation instrument can have avariety of configurations, in an exemplary embodiment the contactablation instrument is selected from the group consisting of cryogenicablation instruments, ablative fluid instruments and heatinginstruments.

In another aspect, a method for ablating tissue about an ostium of aright inferior vein of a heart includes positioning a sheath catheterhaving a deflectable distal end segment with a bent tip element in theleft atrium of a heart, causing the distal end segment to deflect in acompound curve as the catheter is advanced towards an ostium of a rightinferior vein, orienting said sheath catheter such that an ablationinstrument can be delivered through the sheath catheter to a positionproximal to the right inferior vein, and activating the ablationinstrument to form at least one lesion about the right inferior vein. Inone embodiment, the method can further include initially deploying thesheath catheter in the heart over a guide wire, or initially deployingthe sheath catheter together with a stiffening inner dilator over aguide wire. Moreover, the method can include using the sheath cathetertogether with the stiffening inner dilator to create a septal puncturein order to gain access to the left atrium of the heart.

In another embodiment, the step of activating the ablation instrumentfurther includes positioning a radiant energy emitter at a selectedlocation within a balloon catheter that is deployed within the heart viathe sheath catheter and then activating the radiant energy emitter. Theradiant energy emitter can have a variety of configurations, such as anultrasound emitter, a hypersound emitter, a light emitter, a microwaveradiation emitter, a radio-frequency (RF) radiation emitter, an x-rayradiation emitter, an ionizing radiation emitter, a particle beamradiation emitter, or a focused acoustic energy emitter.

In another embodiment, the step of activating the ablation instrumentfurther includes deploying a contact ablation instrument within theheart via the sheath catheter, positioning the contact ablationinstrument at a selected location and then activating the contactablation instrument. While the contact ablation instrument can have avariety of configurations, in an exemplary embodiment it is selectedfrom the group consisting of cryogenic ablation instruments, ablativefluid instruments and heating instruments.

In yet another aspect of the invention, the deflectable sheath catheterof the present invention permits access to all four pulmonary veins. Thecompound curved shape and/or the bent tip structures make the sheathcatheter of the present invention highly maneuverable, permitting thesheath catheter, for example, to arch over the roof of the left atriumin order to direct an ablation instrument to the ostia of the rightpulmonary veins, which are particularly difficult to reach withconventional ablation instruments. Therefore, the present inventionaddresses current problems associated with cardiac access, in particularaccessing the left atrium and inferior pulmonary veins, particularly,the right inferior pulmonary vein of the human heart.

In another aspect of the invention, a cardiac ablation instrumentassembly is disclosed having a deflectable sheath catheter adapted fordisposition within a heart and at least one ablation instrument whichcan be deployed via a proximal hemostasis valve and through thedeflectable sheath catheter to a desired target location. A deflectablesheath catheter is provided (and, optionally a dilator as previouslydescribed above) having a handle at a proximal end and a deflectable tipsection at a distal end. The deflectable tip section provides access tothe heart and target region of cardiac tissue and allows an ablationinstrument to reach the target cardiac tissue, preferably in the leftatrium of the heart to access the pulmonary veins for the treatment ofatrial fibrillation. The sheath is able to “point” the ablation deviceat the ostium of the pulmonary vein and the ablation instrument isadvanced to the target tissue and axial force can be applied to maintaincontact with the target tissue during ablation of the tissue.

In one embodiment, the ablation instrument is deliverable through thedeflectable sheath catheter and includes an energy emitter element thatis independently movable within a lumen of the ablation instrumentfollowing the deployment of the instrument, such that the energy emittercan be disposed at the desired location to deliver radiant energythrough a transmissive region of the instrument to a target tissue site.The ablation instrument can further include a projection balloon, aloneor together with fluid releasing mechanisms, to provide a blood-freetransmission pathway from the energy emitter to the tissue target.

In another embodiment, the ablation instrument includes at least oneanchorage element which can be deployed at the desired location tocontact a cardiac structure and secure the ablation instrument in place.The instrument again includes an energy emitter element movable withinthe lumen of the ablation instrument, following deployment of theinstrument via the deflectable sheath catheter. A projection balloon canagain be employed, alone or together with fluid releasing mechanisms, toprovide a blood-free transmission pathway from the energy emitter to thetissue target.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich like reference numerals designate like parts throughout thefigures, and wherein:

FIG. 1 is a schematic view of an embodiment of the present inventionshowing a deflectable sheath catheter with a handle and a deflectabletip section;

FIG. 2 is a close-up view of an embodiment of the present inventionshowing the deflectable tip section;

FIG. 3A is a schematic, perspective view of another embodiment of thepresent invention showing a variation of a deflectable tip section;

FIG. 3B is a top perspective view of the deflectable tip section of FIG.3A;

FIG. 4A is a schematic view of an embodiment of the present inventionshowing a handle portion and a variable locking deflection actuator;

FIG. 4B is a schematic view of another embodiment of the presentinvention showing a variation of a handle portion and an actuator;

FIG. 4C is a schematic view of another embodiment of the presentinvention showing a handle portion having a hemostasis valve;

FIG. 5 is a schematic, perspective view of an embodiment of the presentinvention showing an elongate catheter body with a pull wire and animbedded pull ring;

FIG. 6 is a schematic, end view of an embodiment of the presentinvention showing an elongate catheter body with a pull wire and anaxially centered lumen;

FIG. 7 is a schematic, perspective view of an embodiment of the presentinvention showing an elongate catheter body having a braided sheathsection;

FIG. 8 is a schematic, perspective view of an embodiment of the presentinvention showing a deflectable tip section having radioopaque bands andirrigation ports;

FIG. 9 is a schematic, perspective view of another embodiment of thepresent invention showing a tapered deflectable tip section;

FIG. 10 is a schematic view of an embodiment of the present inventionshowing a dilator or stiffening element disposed with the sheathcatheter;

FIG. 11 is a schematic illustration of a mechanism for positioning theradiant energy emitter at a selected location relative to the targettissue region;

FIG. 12 is a schematic, cross-sectional view of a coaxial catheterablation instrument according to the invention;

FIG. 13A is a schematic view of an embodiment of the present inventionshowing a deflectable sheath catheter accessing a human heart;

FIG. 13B is a schematic view of the left atrium of a human heart inwhich the deflectable sheath of the present invention is used to accessthe ostium of a left pulmonary vein;

FIG. 13C is a schematic view of the left atrium of a human heart inwhich the deflectable sheath of the present invention is used to accessthe ostium of a right pulmonary vein;

FIG. 14 is a schematic illustration of a further step in performingablative surgery according to the invention, in which the guide wire anddilator are removed and replaced by a radiant energy emitter locatedremote from the lesion site but in a position that permits projection ofradiant energy onto a target region of the heart;

FIG. 15 is a schematic illustration of a step in performing ablativesurgery according to the invention, in which a radiant energy emitter ispositioned to form a lesion at a defined location;

FIG. 16 is a schematic illustration of an alternative step in performingablative surgery according to the invention, in which the radiant energyemitter is positioned to form a lesion at a different defined location;

FIG. 17 is a schematic illustration of a further step in performingablative surgery according to the invention, in which the ablationelement is replaced by a mapping electrode;

FIG. 18 is a schematic illustration of an alternative approach toablative surgery with radiant energy according to the invention, inwhich an ablation instrument without an anchorage element is placed in aposition proximal to a pulmonary vein via the deflectable sheathcatheter;

FIG. 19 is a schematic illustration of a further step in performingablative surgery with the embodiment illustrated in FIG. 18, in whichthe ablation element is a radiant energy emitter and a projectionballoon element is inflated to define a projection pathway for radiantenergy ablation of cardiac tissue;

FIG. 20 is a schematic illustration of a further step in performingablative surgery with the embodiment illustrated in FIG. 19, in whichthe radiant energy emitter is positioned within the projection balloonto deliver radiant energy onto a target region of the heart;

FIG. 21 is a schematic illustration of an instrument according to theinvention in which an asymmetric vein mouth is encountered, and furthershowing how the position of the radiant energy emitter can be adjustedto sense contact and select a location;

FIG. 22 illustrates how a continuous, vein-encircling lesion can beformed by two partially-encircling lesions;

FIG. 23 is a schematic block diagram of the components of anendoscope-guided cardiac ablation system according to the invention;

FIG. 24 is a schematic illustration of one embodiment of a radiant lightenergy emitter according to the invention;

FIG. 25 is a schematic illustration of another embodiment of a radiantlight energy emitter according to the invention;

FIG. 26 is a schematic illustration of an alternative embodiment of aradiant energy emitter according to the invention employing ultrasoundenergy;

FIG. 27 is a schematic illustration of an alternative embodiment of aradiant light energy emitter according to the invention employingmicrowave or ionizing radiation;

FIG. 28 is a schematic cross-sectional illustration of one embodiment ofendoscope and ablator assembly according to the invention;

FIG. 29 is an end view, schematic illustration of the endoscope andablator assembly shown in FIG. 28;

FIG. 30 is a schematic view of a contact heating ablation deviceemploying the endoscope-guiding apparatus of the present invention;

FIG. 31 is a schematic view of a cryogenic ablation device employing theendoscope-guiding apparatus of the present invention;

FIG. 32 is a schematic view of an ultrasound heating ablation deviceemploying the contacting sensing apparatus of the present invention; and

FIG. 33 is a schematic illustration of a translation system forindependently positioning the endoscope and ablation components of anendoscope/ablator assembly during a procedure.

DETAILED DESCRIPTION

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the methods and devices disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the methods anddevices specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the present invention is defined solely by the claims. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the present invention.

The present invention provides devices and methods for the treatment ofatrial fibrillation. In one embodiment a deflectable sheath catheterincludes an elongate catheter body having proximal and distal ends, thedistal end having a distal tip region that includes a plurality offlexible segments with varying degrees of stiffness. A handle portioncan be located at the proximal end of the catheter body to provide asteering mechanism that causes the distal tip region to deflectaccording to a compound curve or a spiral curve. Although described inconnection with cardiac ablation procedures, it should be clear that thedevices and methods of the present invention can be used for a varietyof other procedures where treatment with radiant energy is desirable,including laparoscopic, endoluminal, perivisceral, endoscopic,thoracoscopic, intra-articular, and hybrid approaches.

Before discussing the features of the devices and methods disclosedherein, it should be understood that:

As used herein, the term “balloon” encompasses deformable hollow shapesthat can be inflated into various configurations such as a balloon,circle, tear drop, or any other shape depending upon the requirements ofthe particular cavity. Moreover, the balloon can also have any number(i.e., multiple) of chamber configurations. The balloon elements canalso have a variety of forms, and can be either elastic or simplycapable of unfolding or unwrapping into an expanded state.

As used herein, the term “catheter” encompasses any hollow instrumentcapable of penetrating body tissue or interstitial cavities andproviding a conduit for selectively injecting a solution or gas,including without limitation, venous and arterial conduits of varioussizes and shapes, bronchoscopes, endoscopes, cystoscopes, culpascopes,colonscopes, trocars, laparoscopes and the like. The term “catheter” isalso intended to encompass any elongate body capable of serving as aconduit for one or more of the ablation, expandable or sensing elementsdescribed herein, e.g., energy emitters, balloons and/or endoscopes.Specifically, in the context of coaxial instruments, the term “catheter”can encompass either the outer catheter body or sheath or otherinstruments that can be introduced through such a sheath. The use of theterm “catheter” should not be construed as meaning only a singleinstrument but rather is used to encompass both singular and pluralinstruments, including coaxial, nested, and other tandem arrangements.Moreover, the terms “deflectable sheath catheter” or “steerablecatheter” or “guiding catheters” are used interchangeably to describecatheters having at least one lumen through which instruments ortreatment modalities can pass. Such deflectable sheath catheters can beused, for example, for transeptal passage of ablation instruments andthe like into the left atrium of the heart.

As used herein, the term “compound curve” refers to a curve that canhave a variable radius of curvature along different portions of thecurve. The curvature can increase or decrease and can be a continualchange or take the form of segmented arcs where the radius of curvatureis constant over a given length but varies from one arc to the next. Thechange in curvature of the compound curve can also be progressive orvarying in accordance with other patterns.

As used herein, the terms “circumferential” and/or “curvilinear,”including derivatives thereof, are intended to mean a path or line whichforms an outer border or perimeter that either partially or completelysurrounds a region of tissue, or separate one region of tissue fromanother. Further, a “circumferential” path or element may include one ormore of several shapes, and may be for example, circular, annular,oblong, ovular, elliptical, semi annular, or toroidal.

As used herein, the term “continuous” in the context of a lesion isintended to mean a lesion that substantially blocks electricalconduction between tissue segments on opposite sides of the lesion.

As used herein, the term “lumen,” including derivatives thereof, in thecontext of biological structures, is herein intended to mean any cavityor lumen within the body which is defined at least in part by a tissuewall. For example, cardiac chambers, the uterus, the regions of thegastrointestinal tract, the urinary tract, and the arterial or venousvessels are all considered illustrative examples of body spaces withinthe intended meaning. The term “lumen” including derivatives thereof, inthe context of catheters is intended to encompass any passageway withina catheter instrument (and/or track otherwise joined to such instrumentthat can serve as a passageway) for the passage of other componentinstruments or fluids or for delivery of therapeutic agents or forsampling or otherwise detecting a condition at a remote region of theinstrument.

As used herein, the term “radiant energy” includes ultrasound, focusedultrasound, hypersound, and other forms of acoustic energy as well aslight (including visible, ultraviolet and infrared radiation), microwaveradiation, radio-frequency (RF) radiation, x-ray radiation, ionizingradiation and other forms of electromagnetic or particle beam orradiation as well as focused acoustic energy.

As used herein, the term “ablative energy” is intended to encompass anyand all forms of radiant energy (as described above) as well as contactablation mechanisms, such as the application of heat by conductive orconvective means and/or the application of cryogenic treatments and/orthe use ablative chemical or thermal fluids (either gaseous or liquid)to form a lesion.

As used herein, the term “transparent” includes those materials thatallow transmission of energy through, for example, the primary balloonmember. While a variety of materials can be used, such as transparentmaterials include fluoropolymers, for example, fluorinated ethylenepropylene (FEP), perfluoroalkoxy resin (PFA), polytetrafluoroethylene(PTFE), and ethylene-tetrafluoroethylene (ETFE) or polyester resinsincluding polyethylene teraphathalate (PET), the preferred transparentmaterial should not significantly impede (e.g., result in losses of over20 percent of energy transmitted) the energy being transferred from anenergy emitter to the tissue or cell site.

As used herein, the “Shore (Durometer) test” refers to a commonly usedmethod of measuring the resistance of plastics toward indentation andproviding an empirical hardness value. Shore Hardness, using either theShore A or Shore D scale, is the preferred method for rubbers/elastomersand is also commonly used for ‘softer’ plastics such as polyolefins,fluoropolymers, and vinyls. The Shore A scale is used for ‘softer’rubbers while the Shore D scale is used for ‘harder’ ones. Unlessotherwise noted, stiffness ratings referred herein are based on theShore (Durometer) test.

As used herein, a “transseptal approach” refers to a surgical techniquethat involves the puncture of the intra-atrial septum followed byadvancement of a catheter into the left atrium and left ventricle.

As used herein, the term “vessel” or “blood vessel” includes, withoutlimitation, veins, arteries, and various chambers or regions of theheart, such as the atria, ventricles, coronary sinus, vena cava and, inparticular, the ostia or atrium of the pulmonary veins.

As used herein, the terms “visual,” “visualize” and derivatives thereofdescribe both human and machine uses of reflectance data. Such data cantake the form of images visible to a clinician's eye or any machinedisplay of reflected light, e.g., in black & white, color or so-called“false color” or color enhanced views. Detection and display ofreflected energy measurements outside the visible spectrum are alsoencompassed. In automated systems such visual data need not be displayedbut rather employed direct by a controller to aid in the ablationprocedure.

FIGS. 1 to 33 illustrate embodiments of the present invention relatingto devices and methods for percutaneous access to the heart, and inparticular, the left atrium via a transseptal approach. FIG. 1 shows oneembodiment of a deflectable sheath catheter 10 having proximal anddistal ends 11, 12 connected by an elongate catheter body 20. While theproximal and distal ends 11, 12 can have a variety of configurations, asshown the proximal end 11 includes a handle portion 40 and a variablelocking actuator 50, and the distal end 12 includes a deflectable tipsection 30 (the handle 40 and the tip 30 will be discussed in moredetail below).

The catheter body 20 can have any configuration suitable for insertioninto and/or through a vein or artery, such as circular, oblong orovular, however as shown the catheter body 20 is ovular. The catheterbody 20 can also have at least one lumen 21 formed therein and extendingtherethrough. While the lumen 21 can also be formed in a variety oflocations within the catheter body 21, preferably the lumen 21 iscentrally located. The lumen 21 can have a variety of shapes, such ascircular, oblong or ovular, however in an exemplary embodiment the lumen21 has a shape that is complementary to the shape of the catheter body20, e.g., ovular.

The elongate catheter body 20 can include any number of flexible wallsegments to allow for movement thereof. For example, the catheter body20 can be one continuous segment. Alternatively, the catheter body 20can have any number of flexible segments, such as two, three, four,five, six, etc., at least one of which has a different stiffness thanthe others. As shown, the catheter body 20 has five flexible segments a,b, c, d, and e. The flexible segments a, b, c, d, and e can have anystiffness configuration that allows the catheter 10 to move within theheart or surrounding area, however in an exemplary embodiment eachflexible segment a, b, c, d, and e has a different stiffness. Thevariation of the stiffness of the flexible segments can be random oralong a gradient and, as shown in FIG. 1, the stiffness of the flexiblesegments a, b, c, d, and e can be a gradient of distally decreasingstiffness along the length of the body 20, e.g., segment a can have astiffness rating of “72D,” segment b can have a stiffness rating of“63D,” segment c can have a stiffness rating of “55D,” segment d canhave a stiffness rating of “40D,” and segment e can have a stiffnessrating of “35D.” One skilled in the art will appreciate that thevariation in the stiffness of the segments a, b, c, d, and e allows thedeflectable tip to deflect along a compound curve, or alternatively, aspiral curve.

Each segment can also have a variety of lengths, preferably ranging from1 mm to 100 mm. Each segment can have the same length, or each sectioncan vary in length from one another by either random variations or on acontinuous gradient (such as the distal decrease in length shown in FIG.1). Moreover, the deflectable tip section 30 can be varied in length,however in an exemplary embodiment is in the range of about 20 mm to 20cm.

The elongate catheter body 20 can be made from a variety of flexible,biocompatible polymers such that different stiffness ratings are able tobe formed. One such polymer that allows for the formation of differentstiffness ratings is Pbax plastic. The catheter body 20 can also includean interior lining made from the same or a different polymer material.Moreover, different portions of the catheter body 20 can be made ofdifferent materials, e.g., the deflectable tip 30 can be made from thesame or different material as the elongate catheter body 20 describedabove.

FIGS. 2 to 9 further illustrate various components of the catheter ofFIG. 1, such the handle 40 and the deflectable tip 30, as well asvarious features of the catheter that can assist a surgeon in accessingthe desired tissue.

FIG. 2 illustrates the distal end 12 of the deflectable sheath catheter.As shown the distal end 12 includes a pull wire 25 that extends betweena variable locking actuator (such as variable locking actuator 50 shownin FIG. 1) on the handle portion 40 (such as handle portion 40 shown inFIG. 1) and the tip 30 such that the tip 30 that is movable within thewall 24 of the elongate catheter body 20.

The pull wire 25 can have a variety of configurations, however in anexemplary embodiment, the pull wire 25 is preferably cylindrical inshape and can be sized to fit a channel within the wall 24 of theelongate catheter body 20 without communication with the central lumen21. The pull wire 25 can also be attached to the actuator 50 and thedeflectable tip 30 in a variety of ways, and in an exemplary embodiment,the pull wire 25 can be fastened at its proximal end to the actuator 50(shown in FIG. 1) and at the distal end to the deflectable tip section30. A variety of both fixed and removable fastening means can be used tomate the pull wire 25 with both the actuator 50 and the deflectable tip30, such as clamps, screws, bolts, anchors, and hooks. Alternatively,the distal end of the pull wire 25 can be welded to a stainless steelring which is embedded in the distal end of the catheter body 20.

Upon movement of the pull wire 25, the deflectable tip section 30 candeflect to varying degrees depending upon the amount of lateral movementof the pull wire 25. In an exemplary embodiment, the deflectable tipsection can move in the range of about 5° to about 270°, more preferablyfrom about 10° to about 200°.

FIGS. 3A and 3B show another embodiment of the present invention wherethe deflectable tip section 30 can be pre-formed or bent, prior toinsertion into a patient, through one or more planes. While the bend 31can be any degree that allows a surgeon to access the heart, in anexemplary embodiment, the bend 31 is formed in a posterior direction inthe range of about 20° to about 90° relative to the heart (shown asangle α). Moreover, angle α can be between about 5° to about 90°relative to the central axis of the catheter in an unflexed state, fromabout 10° to about 60° relative to the central axis of the catheter inan unflexed state, or, more preferably between about 15° to about 45°relative to the catheter in an unflexed state. One skilled in the artwill appreciate that such a bend 31 facilitates more effective access tothe heart, especially to the superior and inferior pulmonary veins ofthe heart.

The bend 31 of the deflectable tip section 30 can made in any mannerknown in the art that allows it to maintain its position throughout therange deflection relative to its plane of displacement. For example, thebend 31 can be formed during manufacturing by molding or extrusion.Alternatively, the bend 31 can be formed prior to use, that is the bend31 can be formed from a shape memory metal such as NITINOL (as acronymfor NIckel TItanium Naval Ordnance Laboratory) family of intermetallicmaterials, which contain a nearly equal mixture of nickel (55% byweight) and titanium.

One skilled in the art will appreciate that the bent tip 31 isparticularly useful in accessing all four pulmonary veins because theostium of these veins do not all lie in a single plane of deflection.

Moreover, the bend 31 can be used in conjunction with a pull wire 25,similar to that as discussed with respect to FIG. 2, and one skilled inthe art will appreciate that the combination of the pull wire 25 and thebend 31 allow a surgeon precision control to access various locationswithin the heart.

FIGS. 4A to 4C illustrate a deflectable sheath catheter 10 having oneembodiment of a handle portion 40 with a variable locking actuator 50,features to connect the actuator 50 to a pull wire (such as pull wire 25discussed above), as well as various port and valve assemblies.

The handle portion 40 can have any configuration known in the art,however as shown, the handle 40 can include a central lumen 45 connectedto lumen 21 of the elongate catheter body 20. Lumen 45 can have avariety of configurations, e.g., circular, oblong or ovular, however inan exemplary embodiment the lumen 45 has a shape that is complementaryto the shape of the lumen 21 of the elongate catheter body 20 (that is,ovular). The lumen 45 can also terminate in an end port 47 (as will bediscussed in more detail below).

While the handle portion 40 can be either fixedly or removably mated tothe elongate catheter body 20, in an exemplary embodiment, the handleportion 40 is removably mated to the catheter body 20 by any means knownin the art such as a nut and bolt assembly. Alternatively, the elongatecatheter body 20 can extend into the handle portion 40 such that it canconnect to the central lumen 45 at a point proximal to the distal end ofthe handle portion 40. The handle portion 40 can also include means toconnect a pull wire 25 with the actuator 50.

The variable locking actuator 50 can have any configuration that causesthe pull wire 25 to move in a lateral direction along the elongatecatheter body 20. In an exemplary embodiment, the actuator 50 can beconfigured such that it can lock in place, thereby allowing thedeflectable tip section 30 to remain in a deflected position at variouspoints throughout its range of movement. The positions at which theactuator 50 can lock can be determined by the mechanical incrementsdesigned into the variable locking actuator 50 and handle portion 40.While the mechanism can be configured to lock the actuator 50 in avariety of increments, in one embodiment the mechanism can be configuredto lock the actuator 50 at 1° of tip deflection, or every 5° of tipdeflection.

The variable locking actuator 50 can also include a variety of fasteningmeans to either fixedly or removably mate with the pull wire 25, andsuch means can be either a direct or an indirect connection. As shown inFIG. 4A, the pull wire 25 can connect to the variable locking actuator50 via direct connection. In use, as the actuator 50 is displaced in adistal to proximal direction, the pull wire 25 is displaced in the samedirection and thus the deflectable tip section 30 is deflected a desiredamount. To return the deflectable tip section 30 to its un-deflectedposition, the actuator 50 is moved in a proximal to distal direction,thus moving the pull wire 25 in the same direction and allowing the tip30 to uncoil. Alternatively, the pull wire 25 can be indirectlyconnected to the actuator 50 via a pulley mechanism 43 as shown in FIG.4B. While the pulley mechanism 43 can have a variety of configurations,in an exemplary embodiment the pulley mechanism 43 can be housed in thehandle portion 40 such that the pull wire 25 can wrap around the pulley43 and connect to the actuator 50. In use, the actuator 50 is displacedin a proximal to distal direction in order to deflect the tip section 30and the reverse operation can uncoil the tip 30.

The handle portion 40 can also have a variety of port and valveassemblies attached thereto. For, example, as shown in FIG. 4C, anexemplary sideport and valve access assembly can include at least onefluid access sideport 49 and at least one valve 51. The sideport andvalve assembly can be either fixedly or removably mated to the handleportion 40 in a variety of ways, such as by adhesives, press fit, etc.Moreover, the sideport and valve assembly can be mated to the handleportion 40 such that the assembly is in fluid communication with thecentral lumen 45 of the handle 40.

While the sideport 49 can have a variety of configurations, in anexemplary embodiment the sideport 49 is sized such that it can carrysaline or other appropriate fluids, such as a heparin drip, contrastsolution or other medications or agents, into one or more lumens (suchas lumen 21) within catheter body 20 for the treatment and/or diagnosisof ailments afflicting the human vasculature. The valve 51 can be anyvalve known in the art such as a manual valve, a one-way value, atwo-way value or a stop valve.

As noted above, the central lumen 45 of the handle 40 can terminate inan end port 47. While the end port 47 can have a variety ofconfigurations, in an exemplary embodiment the end port 47 includes ahemostasis valve at its proximal end to allow for the insertion of othermedical instruments into the handle portion 40 and subsequently into thelumen 21 of the elongate catheter body 20.

The hemostasis valve can have a variety of shapes and sizes dependingupon the particular procedure and instrumentation required, however inan exemplary embodiment the hemostasis valve can be sized in the rangeof about 2.5 Fr. to about 15 Fr. One skilled in the art will appreciatethat the hemostasis valve allows instruments (such as dilator 150 shownin phantom) to be introduced through the deflectable catheter 40 withoutblood loss through the proximal end of the handle 40 while alsopreventing the introduction of air into the deflectable catheter 40uring insertion of devices through the hemostasis valve.

One skilled in the art will appreciate that the handle portion 40 abovecan be made out of a variety of materials, such as plastic, metal, orany suitable material known in the art.

FIGS. 5 and 6 illustrate another embodiment of the catheter 10 where thepull wire 25 is disposed within the wall 24 of the elongate catheterbody 20. While the pull wire 25 can be disposed within the wall of theelongate catheter body 20 in a variety of ways, as shown the pull wire25 is disposed within a chamber 27 formed within the wall 24, such thatthe pull wire 25 is not in communication with the catheter body 20 orthe central lumen 21 of the catheter 20. Moreover, the distal end of thepull wire 25 can be anchored to the wall 24 of the catheter body 20,preferably with the aid of an anchor ring 25A as shown, to helpdistribute the tensile forces exerted during deflection.

While the chamber 27 can be formed in a variety of locations within thewall, as shown in FIG. 5B, the chamber 27 is located on the same side asthe variable locking actuator 50 in handle portion 40. Thus, in use, thedeflectable tip section 30 deflects angularly toward the lockingactuator 50 (as a result the tip 30 will deflect upwards). Alternatively(not shown), the pull wire can be located in another area of the wallsuch that the tip section can deflect angularly in a differentdirection. In yet another embodiment (also not shown), a deflectablesheath catheter can have two pull wires, each pull wire disposed indifferent chambers of the wall. While each pull wire can be attached tothe actuator either in tandem or separately, in an exemplary embodimenteach pull wire can be attached to the actuator separately to allow thedeflectable tip section to deflect in different directions relative tothe catheter body.

FIG. 7 shows another embodiment of the present invention where the wall24 of the elongate catheter body 20 includes a wire sheath or braidsection 60 for reinforcement. While the braid section 60 can have anyconfiguration that aids the structural reinforcement of the elongatecatheter body 20, as shown the braid section 60 is woven in a crisscrosspattern. The braid section 60 can also have varying strength andthickness depending upon the amount of flexibility desired in theelongate catheter body 20, and can be applied in a various patterns withdifferent densities to achieve the desired variablestiffness/flexibility properties.

The braid section 60 can be placed at a variety of locations along thecatheter body 20, and in an exemplary embodiment it is wrapped aroundthe wall 24 of the elongate catheter body 20. Moreover, the braidsection 60 can be continuous, along the entire length of the wall 24 ofthe elongate catheter body 20, or the braid section 60 can bediscontinuous along the length of the wall 24 of the elongate catheterbody 20 (that is, the braid section 60 can be located in sections aroundthe wall 24 of the elongate catheter body 20, as desired, with sectionsof no braid located in-between the braid sections). In an exemplaryembodiment, the braid section 60 can stop prior to the deflectable tipsection 30 to allow the tip section 30 to deflect as previouslydescribed.

One skilled in the art can appreciate that the braid section 60 can bemade from any material that can provide sufficient reinforcement to thecatheter body 20, including various metal or metal alloys, or variouspolymers.

FIG. 8 shows an embodiment of the present invention where the catheter10 has at least one radio opaque marker band 70 and at least oneirrigation hole 31 located at the distal end of the catheter 10. Whilethe catheter 10 can have any number of marker bands 70, as shown thecatheter 10 has two marker bands 70. The marker bands 70 can be locatedin a variety of locations along the catheter 10, however the markerbands 70 are preferably located at the proximal end 30 a of thedeflectable tip section 30 and near the distal end 30 b of the tipsection 30. Alternatively, for catheters having a taper formed at thedistal end thereof (such as taper 33 discussed below), the marker bandscan be formed proximal to said taper.

The marker bands 70 can have any size that allows the marker bands 70 tobe visible when viewed under x-ray or other biomedical imagery device orprocess known in the art. One skilled in the art will appreciate thatany radio opaque material can be used to form the marker bands, howeverin an exemplary embodiment the marker bands can be formed of gold.Moreover, the catheter material itself may be rendered radio opaque bycompounding the polymer used with barium sulfate (BaSO₄) in aconcentration of about 20-40 percent.

As noted above, the catheter 10 can have any number of irrigation holes31 formed therein to allow for additional irrigation and fluidiccommunication between the central catheter lumen 21 in the elongatecatheter body 20 and the human vasculature. As shown the catheter 10 hasthree holes 31. While the irrigation holes 31 can be located in avariety of locations on the catheter 10, in an exemplary embodiment atleast one irrigation hole 31 is formed in the tip section 30 of thecatheter 10. Alternatively, at least one hole 31 can be formed on theside of the catheter body 20, or, alternatively the tip section 30 ofthe catheter 10. The holes 31 can have any size such that there can befluidic communication between the central catheter lumen 21 in theelongate catheter body 20 and the human vasculature. One skilled in theart will appreciate that the holes 31 can also allow the passage offluids through the central lumen 21 in the event that the distal openingof the central lumen 21 is occluded by tissue contact or thrombus.

FIG. 9 shows another embodiment of a catheter with a deflectable tipsection 30 having a distal taper 33. While the taper 33 can have avariety of configurations, the taper 33 can have a length and amountsuch that the deflectable tip section 30 can be navigated through anartery or vein with ease. Moreover, one skilled the art will appreciatethat the taper 33 allows the tip section 30 to be made from a softermaterial thus rendering it atraumatic to delicate vascular structuresand endocardial tissue.

A variety of devices can be used with the catheter described herein suchas a dilator or an ablation instrument. FIG. 10 shows one embodiment ofthe catheter including a dilator 150. The dilator 150 can have anyconfiguration that allows it to be passed through the catheter and overa guide wire and into the heart, however, as shown the dilator 150 hasproximal and distal ends 149, 151, and can include a central lumen 152formed therein. The central lumen 152 can have any shape and size, suchas circular, ovular or oblong, however here the central lumen 152corresponds in shape to the shape of the catheter (e.g., is ovular), andis adapted to fit snugly within the central lumen of the deflectablesheath catheter, allowing easy insertion of an atrial septum punctureinstrument through the vasculature. One skilled in the art willappreciate that the close fitting nature of the dilator 150 within thedeflectable catheter can prevent the tip 30 of the deflectable catheterfrom prolapsing if axial forces are encountered crossing the atrialseptal puncture site.

The dilator 150 can also have a variety of other features to assist inits placement. For example, the distal end 157 of the dilator 150 can betapered for ease of transition within a vein or vessel. The dilator 150can also be configured to have radio opaque markings, similar to themarker bands 70 described above, at various points along its length orit can be made entirely from a radio opaque material. Alternatively, thedilator can be made from a polymer material and can be bio-compatible.

An ablation instrument 500 can also be used with a deflectable sheathcatheter. While the ablation instrument 500 can have a variety ofconfigurations, the ablation instrument 500 has proximal and distal ends500 a, 500 b and is adapted to pass through an inner lumen of thedeflectable catheter into position in proximity to a target treatmentsite. As shown in FIG. 11, the ablation instrument 500 can include aradiant energy emitter. While the radiant energy emitter can have avariety of configurations, in an exemplary embodiment it includes anelongate body 589 as well as a translatory mechanism 580 for controllingits movement within an ablation instrument 500 following its deliverythrough the deflectable sheath catheter. The translatory mechanism 580can have a variety of configurations, and as shown it can beincorporated into a handle 584 in the proximal end 500 a of the ablationinstrument 500. Moreover, the translatory mechanism 580 can have avariety of control mechanisms, such as either an automated or manualcontrol mechanism, however in an exemplary embodiment translatorymechanism 580 has a thumb wheel 586 that can engage the elongate body582 of the radiant energy emitter 540 to control advancement andretraction of the emitter.

One skilled in the art will appreciate that catheter disclosed hereincan incorporate a variety of other designs and features in addition tothose features disclosed above. For example, similar to U.S. Pat. No.6,522,933 entitled “Steerable Catheter with a Control Handle having aPulley Mechanism,” which is herein incorporated by reference, thecatheter can have a control handle having a piston slidably mounted inthe handle housing and a pulley fixedly attached, either directly orindirectly, to the handle housing at a location proximal to the proximalend of the piston by first and second puller wires. The handle portioncan also be shaped as a pistol grip such that the handle is under aspring-loaded force to maintain a backpressure on the handle similar tothat as disclosed in U.S. Pat. No. 6,679,873 entitled “Method for usinga Steerable Catheter Device,” which is herein incorporated by reference.

Additionally, the catheter can have a distal tip with a spring elementbiased to return the tip to a substantially straight position similar tothat seen in U.S. Pat. No. 6,702,780 entitled “Steering Configurationfor Catheter with Rigid Distal Device,” herein incorporated byreference. The catheter can also include compression coils or flatflexible wires such that when a user engages a steering assembly, adistal end of the tubular body can be selectively bent in a firstdirection or in a second direction depending upon which coil or wire isactively displaced as seen in U.S. Pat. No. 6,579,278 entitled“Bi-Directional Steerable Catheter with Asymmetric Fulcrum,” hereinincorporated by reference, or a deflection mechanism similar to that asdisclosed in U.S. Pat. No. 6,251,092 entitled “Deflectable GuidingCatheter,” also herein incorporated by reference.

Moreover, the catheters of the present invention can be constructed withany biocompatible materials known in the art such for example, silastic,polyethylene, Teflon, polyurethanes, etc. Moreover, the lumen formedtherein can be lined with a stiffening element.

FIGS. 12 to 22 illustrate methods for performing ablative surgery usingthe catheter disclosed above. FIG. 12 is a schematic illustration of amethod of performing ablative surgery with radiant energy according tothe invention. As shown, after the sheath catheter 10 is introduced intoa heart and positioned in front of a pulmonary vein 516, the ablationinstrument 500 is slid through the sheath catheter 10 to the targettissue site.

Ablation instrument 500 is similar to the ablation instrument discussedabove with respect to FIG. 11, however also includes a projectionballoon structure 526 attached to catheter 10 and at least one internalfluid passageway (not shown) for inflation of the balloon 526. While theballoon 526 can be attached to the catheter 10 in a variety of ways, inan exemplary embodiment the balloon 526 is sealed to the body of thecatheter 524 by distal seal 525 and proximal seal 527, such that theintroduction of an inflation fluid into the balloon 526 can inflate theballoon. One having skill in the art will appreciate that projectionballoon 526 can be inflated to define a projection pathway for radiantenergy ablation of cardiac tissue.

While the projection balloon 526 can have a variety of configurations,the projection balloon 526 can be preshaped to form parabolic like orvarious other shapes to assist in seating the instrument at the mouth ofa pulmonary vein or otherwise engaging the vein ostium or otheranatomically defined regions of the heart. While such shapes can beformed in a variety of ways, in an exemplary embodiment they are formedby shaping and melting a TEFLON® film in a preshaped mold to the desiredform. Alternatively, the projection balloons 526 can be made from a thinwall of polyethylene teraphthalate (PET) membranes. While the membranescan have a variety of thicknesses, in an exemplary embodiment, themembranes have a thickness of about 5-50 micrometers.

As noted above, following inflation, the projection balloon 526 can befilled with a radiation-transmissive fluid 529 so that radiant energyfrom an energy emitter can be efficiently passed through the instrumentto a target region 552 of cardiac tissue. The ablative fluid 529 in thiscontext is any fluid that can serve as a conductor of the radiantenergy, e.g., any physiologically compatible fluid, such as saline, orany other non-toxic aqueous fluid. The fluid 529 can also serve anirrigation function by displacing any blood within the path of theradiant energy, which could otherwise interfere with the radiant lightenergy transmission to the target region 552.

While the fluid 529 can enter the balloon 526 in a variety of ways, inan exemplary embodiment the fluid 529 can be released via one or moreexit ports 536 to flow between the projection balloon 526 and thesurrounding tissue, thereby filling any gaps where the balloon 526 doesnot contact the tissue. Moreover, the radiation transmissive fluid 529can be continually released (e.g., between the balloon 526 and thetarget region 552) to ensure efficient transmission of the radiantenergy when the instrument is deployed.

One skilled in the art will appreciate that the projection balloon 526can not only contact the target tissue in order to ensure radiant energytransmission, but the projection balloon 526 can also serve to clear avolume of blood away from the path of the energy emitter.

Another method disclosed herein is based on the discovery that infraredradiation is particularly useful in forming photoablative lesions. Thus,an ablative instrument can emit radiation at a wavelength in a rangefrom about 800 nm to about 1000 nm, and preferably emit at a wavelengthin a range of about 915 nm to about 980 nm such that a lesion is formed.One skilled in the art will appreciate that the emission of radiation atwavelengths in the range of about 915 nm or 980 nm allows for theoptimal absorption of the infrared radiation by cardiac tissue.

In a further aspect of the invention, the ablation instrument canperform photoablation, e.g., employing tissue-penetrating radiant energyto create the electrical conduction block. It has been discovered thatradiant energy, e.g., projected electromagnetic radiation or ultrasound,can create lesions in less time and with less risk of the adverse typesof surface tissue destruction commonly associated with prior artapproaches. One skilled in the art will appreciate that unlikeinstruments that rely on thermal conduction or resistive heating,controlled penetrating radiant energy can be used to simultaneouslydeposit energy throughout the full thickness of a target tissue, such asa heart wall, even when the heart is filled with blood. Moreover,radiant energy can also produce better-defined and more uniform lesions.

In addition to infrared light-based ablation devices, other forms ofradiant energy can also be useful including, but not limited to, otherwavelengths of light, ultrasound, hypersound, radio frequency radiation,microwave radiation, x-rays, and gamma-rays. Moreover, contact ablationmechanisms, such as the application of heat by conductive or convectivemeans, the application of cryogenic treatments, and/or the use ablativechemical or thermal fluids (either gaseous or liquid) can also be usedto form a lesion.

FIG. 13A illustrates an alternative method of cardiac access asdisclosed herein. As shown, the human heart 130 has a right atrium 131,a right ventricle 132, a left ventricle 133 and a left atrium 134. Leftpulmonary veins 135, 136 and right pulmonary veins 137, 138 drain intothe left atrium, as shown schematically. The method can includepositioning a guide wire 506 in the right atrium 131. The deflectablesheath catheter 10 is then passed over the guide wire, and the distalend of the deflectable sheath catheter 10 is deflected such that the tipof the catheter 10 provides access to the pulmonary veins in the leftatrium of the heart 135, 136.

Once in the pulmonary veins 135, 136, as shown in FIG. 13B, thedeflectable tip section of the catheter 10 can be locked in a bentposition pointing at the ostium/atrium of a left pulmonary vein 135 orthe surrounding endomyocardium such that an ablation instrument 500 canbe introduced into the target region and the target region ultimatelyablated. Alternatively, following introduction into the target regionthe deflectable catheter 10 can be unlocked and repositioned as shown inFIG. 13C. One skilled in the art will appreciate that the deflectablesheath catheter 10 disclosed herein allows an operator to deflect thecatheter 10 at least 180° so that the deflectable tip section of thecatheter 10 can “loop over” or arch over the roof of the atrium in orderto point the distal section of the catheter 10 at the ostium of theright pulmonary veins 137, 138.

Not only can the catheter 10 deliver ablation energy, but it can alsodeliver treatment fluid, such as saline, or a medical instrument, suchas an ablation instrument, to each of the four pulmonary veins in orderto access, align, and aid in the treatment of atrial fibrillation byisolation (ablation) of the pulmonary veins. One skilled in the art willalso appreciate that the deflectable catheter 10 also facilitatescontact with the pulmonary vein ostia by allowing the clinician to applyaxial force to an ostium with the ablation instrument, as this axialforce typically cannot be applied with a deflectable ablation instrumentalone.

As shown in FIG. 14, another embodiment of a method for ablating cardiactissue includes positioning a guide wire in proximity to a target regionof cardiac tissue 552 and coupling a deflectable sheath catheter 10having at least one lumen 514 to the positioned guide wire via the lumen514, such that the sheath catheter 10 can be passed over the guide wireto a target region of cardiac tissue 552. The sheath catheter 10 canfurther include a concentric dilator or stiffening element that servesas a lining within the catheter 10, and in such applications the methodfurther comprises passage of the catheter 10 and dilator assembly overthe guide wire. Next, the deflectable sheath catheter 10 (and theoptional stiffening element) can be passed over the guidewire into aposition within the heart and used to create a transeptal puncture intothe left atrium. The guide wire can be removed before or after theseptum is punctured. Once the sheath catheter 10 is positioned inproximity to the target site (e.g., the ostium of a pulmonary vein) thedilator can be removed and replaced with an ablation instrument slidablymovable within a lumen of the deflectable sheath catheter 10 such thatit can be disposed at the desired location (such as target tissue 552).

While the energy emitter can vary depending upon the procedure, in theillustrated embodiment, the energy emitter 540 is a radiant energyemitter having at least one optical fiber 542 coupled to a distal, lightprojecting, optical element 543, which cooperate to project ablativelight energy through the instrument to the target site 552. In onepreferred embodiment, the optical element 543 is a lens element capableof projecting an annular (ring-shaped) beam of radiation, as describedin more detail in commonly owned U.S. Pat. No. 6,423,055 issued Jul. 22,2002, herein incorporated by reference. The method further includesactivating the ablation instrument in proximity to the target tissueregion to ablate tissue and form a conduction block.

FIGS. 15 and 16 illustrate another method disclosed herein wherein asurgeon can select the location of a lesion independent of theinstrument design. The method is similar to that as discussed withrespect to FIG. 14, however, because the radiant energy emitter 540 doesnot require contact with a target tissue region 552 and is, in fact,decoupled from the rest of the ablation instrument, the presentinvention permits the clinician to select a desired target region bysimply moving the emitter 540 within the lumen 514 of the deflectablesheath catheter 10. As shown in FIG. 15, the radiant energy emitter 540can be positioned to form a wide circumferential lesion (when the shapeof the pulmonary vein ostium warrants such a lesion) by positioning theradiant energy emitter 540 at the rear of the projection balloon 526 ata distance from the target tissue. Alternatively, positioning theradiant energy emitter 540 closer to the front of the project balloon526, as shown in FIG. 16, can form a smaller diameter lesion. Oneskilled in the art will appreciate that a smaller lesion can be usedwhen the geometry of the vein ostium presents a more gradual change indiameter, as shown. Moreover, it should be appreciated that it may bedesirable to change the intensity of the emitted radiation dependingupon the distance it must be projected; thus a more intense radiantenergy beam may be desirable in the scheme illustrated in FIG. 15 versusthat shown in FIG. 16.

In another embodiment, shown in FIG. 17, a mapping electrode catheter588 can be passed through the ablation instrument, after the instrumenthas been delivered through the deflectable sheath catheter 10 andpositioned within a pulmonary vein 504. Using the mapping electrode 588,an electrical pulse can be applied to determine whether the lesionformed by the radiant energy emitter (as described above) is sufficientto serve as a conduction block. Various techniques for verifying theformation of an electrical conduction block are known by those skilledin the art. In one simple approach, a coronary sinus catheter applies avoltage pulse, and the mapping catheter electrode 588 is touched to theinner wall of the pulmonary vein 504. If no signal (or a substantiallyattenuated signal) is detected, a conduction block can thereby beconfirmed. It should also be appreciated that the mapping electrode 588can, in some instances, be used even before the projection and/or anchorballoons 526 are removed.

Moreover, the methods described in FIGS. 12 to 17 can also include theuse of an anchoring element, such as an anchoring balloon, to maintainthe catheter the desired position of the catheter with respect to thetarget tissue. However, as shown in FIG. 18 ablative surgery withradiant energy according to the invention can be performed without theneed for an anchoring balloon. As shown in FIG. 18, a guide wire 506 canbe introduced into a heart and passed into the proximity of a pulmonaryvein 504. The deflectable sheath catheter (with or without a stiffeningliner or dilator element) can be passed over the guide wire 506 and intothe heart. Following insertion into the heart, the deflectable sheathcatheter can serve as a platform for the introduction of an ablationinstrument. The ablation instrument can be a balloon catheter similar toprojection balloon 526 discussed above having an elongate body with atleast one internal fluid passageway (not shown) for inflation of theballoon 526, and which is sealed to the body of the catheter by distalseal 521 and proximal seal 522, such that the introduction of aninflation fluid into the balloon 526 can inflate the balloon 526. Oneskilled in the art can also appreciate that, even without the use of anytype of anchoring element, the deflectable sheath catheter not only canpoint the ablation instrument in the proper direction but also permitsthe clinician to apply sufficient axial pressure to seal the balloonagainst the mouth of a pulmonary vein.

As noted above, following insertion, the projection balloon 526 can thenbe inflated to define a projection pathway for radiant energy ablationof cardiac tissue. As shown in FIG. 19, the expanded projection balloon526 defines a staging through which radiant energy can be projected inaccordance with the invention. In one preferred embodiment, and similarto that discussed in FIG. 12, the projection balloon 526 is filled witha radiation-transmissive fluid so that radiant energy from an energyemitter can efficiently pass through the instrument to a target regionof cardiac tissue.

FIG. 20 is a schematic illustration of a further step in performingablative surgery with the device of FIGS. 18 and 19, in which the guidewire and dilator are removed from the deflectable sheath catheter andreplaced by an ablation instrument 540 located remote from the desiredlesion site 552 (but still in a position that permits projection ofradiant energy onto a target region of the heart). In the illustratedembodiment, the radiant energy emitter 540 includes at least one opticalfiber 542 coupled to a distal light projector, such as optical element543, which cooperate to project ablative light energy through theinstrument induce photocoagulation of cardiac tissue within the targetregion. In one preferred embodiment, optical element 543 is again a lenselement capable of projecting an annular (ring-shaped) beam ofradiation, as described in more detail in commonly owned U.S. Pat. No.6,423,055 issued Jul. 22, 2002, herein incorporated by reference.Alternatively, as noted above, the radiant energy emitter can be anultrasound or microwave energy source.

Endoscopic guidance systems can further be used to position any movablepoint source of ablative energy, e.g., a rotating contact or radiantablation element in lieu of a slidably positionable source or togethertherewith, such that the desired path can be visualized and followed bythe ablation element. Most generally, endoscopic guidance systems can beused together with various fluoroscopic or other imaging techniques tolocation and position any one of the various instruments necessary forcardiac ablation.

The ability to position the energy emitter, especially when radiantlight is employed as the ablation modality, also permits endoscopicaiming of the energy. For example, an aiming light beam can betransmitted via the catheter to the target site such that the physiciancan visualize where the energy will be delivered. Thus, endoscopicguidance permits the user to see where energy will be projected atvarious locations of the energy emitter. For example, if the instrumentis designed to project light in an annular ring around the ostium of apulmonary vein, the aiming beam can be projected down the same opticaldelivery path as would the radiant energy. If the “aiming ring” isprojected onto a region of the atrium where a clear transmission pathwayis seen, there is continuous contact (or the desired lesion path isotherwise cleared of blood), and the physician can begin the procedure.If, on the other hand, a clear transmission pathway is not seen at aparticular location of the ablation element, then the ablation elementcan be moved until a clear lesion pathway is found. Although this“aiming” feature of the invention has been described in connection withradiant light energy sources, it should be clear that “aiming” can beused advantageously with any radiant energy source and, in fact, it canalso assist in the placement of fixed or contact-based ablationelements. Most generally, endoscope-guidance can be combined with anaiming beam in any cardiac ablation system to improve positioning andpredetermination of successful lesion formation.

FIGS. 21 and 22 further illustrate the unique utility of themulti-positionable, radiant energy ablation devices of the presentinvention in treating the complex cardiac geometries that are oftenencountered. As shown, the mouths of pulmonary veins (such as pulmonaryvein 504) typically do not present simple, funnel-shaped, or regularconical surfaces. Instead, one side of the ostium 504B can present agentle sloping surface, while another side 504A presents a sharper bend.Because the position of the heating band of the prior art devices isfixed, it does not fully contact the target tissue and a lesion that isin the form of an arc, or incompletely formed ring-type, will result.Such a lesion is typically insufficient to block conduction.

FIG. 21 illustrates how the slidably positionable energy emitters of thepresent invention can be used to avoid this problem. Three potentialpositions of the emitter 540 are shown in the figure (labeled as “A”,“B” and “C”). As shown, positions A and C may not result in optimallesions because of gaps between the balloon 526 and the target tissue.Position B, on the other hand, is preferable because circumferentialcontact has been achieved. Thus, the independent positioning of theenergy source relative to the balloon 526 allows the clinician to “dial”an appropriately ring size to meet the encountered geometry. (Althoughthree discrete locations are shown in FIG. 21, it should be clear thatemitter can be positioned in many more positions and that the locationcan be varied in either discrete intervals or continuously, if sodesired.)

Moreover, in some instances the geometries of the pulmonary vein 504 (orthe orientation of the projection balloon 526 relative to the ostium)may be such that no single annular lesion can form a continuousconduction block. Again, the present invention provides a mechanism foraddressing this problem by adjustment of the location of the energyemitter to form two or more partially circumferential lesions. As shownin FIG. 22, the devices of the present invention can form a first lesion194 and a second lesion 196, each in the form of an arc or partial ring.Because each lesion 194, 196 has a thickness (dependent largely by theamount of energy deposited into the tissue) the two lesions 194, 196 canaxially combine, as shown, to form a continuous encircling orcircumscribing lesion that blocks conduction.

FIG. 23 is a schematic block diagram showing an ablation instrumentformed as an endoscope/ablator assembly 132 comprising endoscope 176 andablation element 540 connected to an analyzer system. The analyzersystem further includes a detector 134 for detecting reflected light(and for generating an image). The output of the detector 134 can betransmitted to a display 136 for clinician viewing. The display 136 canbe a simple eyepiece, a monitor, or a heads-up projection onto glassesworn by members of the surgical team. The system can further include anenergy source 139, a controller 137, and a user interface 138. In use,the endoscope 176 captures images which can be processed by the detector134 and/or controller 137 to determine whether a suitable ablation pathcan be created. An aiming light source 131 can also be used visualizethe location where energy will be delivery to the tissue. If a suitableablation path is seen by the surgeon, the controller 137 can transmitradiant energy from the ablation element 139 to a target tissue site toeffect ablation. Moreover, the controller 137 can provide simulateddisplays to the user, superimposing, for example, a predicted lesionpattern on the image acquired by the detector or superimposing dosimetryinformation based on the lesion location. The controller 137 can furtherinclude a memory for storing and displaying data, such as pre-procedureimages, lesion predictions and/or actual outcomes, as well as a safetyshutoff to the system in the event that a clear transmission pathwaybetween the radiant energy source and the target tissue is lost duringenergy delivery.

FIG. 24 is a schematic illustration of one embodiment of a radiantenergy emitter 140A according to the invention. While the energy emitter140A can have a variety of configurations, as shown the energy emitter140A can be a radiant energy emitter 140A that includes an optical fiber142 in communication with an annulus-forming optical waveguide 144having a concave interior boundary or surface 145. The waveguide 144passes an annular beam of light to a graded intensity (GRIN) lens 146,which serves to collimate the beam, keeping the beam width the same,over the projected distance. Thus, the beam that exits from the distalwindow 148 of energy emitter 140 will expand (in diameter) overdistance, but the energy will remain largely confined to a narrowannular band.

In one preferred embodiment, the radiant energy is electromagneticradiation, e.g., coherent or laser light, and the energy emitter 140Aprojects an hollow cone of radiation that forms an annular exposurepattern upon impingement with a target surface. Generally, the angle ofprojection from the central axis of the optical fiber 142 or waveguide144 will be between about 20° and 60° (for a total subtended angle ofabout 40° to about 120°). Moreover, the diameter of the annular beam oflight will be dependent upon the distance from the point of projectionto point of capture by a surface, e.g., a tissue site, e.g., aninterstitial cavity or lumen. Typically, when the purpose of the radiantenergy projection is to form a transmural cardiac lesion, e.g., around apulmonary vein, the diameter of the annular beam will be between about10 mm and about 33 mm, preferably greater than 10 mm, greater than 15mm, greater than 20 mm, and most preferably, greater than or equal to 23mm. Typically, angle of projected annular light is between about 20° andabout 60°, preferably between about 45° and about 55°, most preferablyin some applications about 50° (total subtended angle 100°).

Preferred energy sources for use with the percutaneous ablationinstruments of the present invention include laser light in the rangebetween about 200 nanometers and 2.5 micrometers. In particular,wavelengths that correspond to, or are near, water absorption peaks areoften preferred. Such wavelengths include those between about 805 nm andabout 1060 nm, preferably between about 900 nm and 1000 nm, mostpreferably, between about 915 nm and 980 nm. In a preferred embodiment,wavelengths around 915 nm or around 980 nm are used during endocardialprocedures. Suitable lasers include excimer lasers, gas lasers, solidstate lasers and laser diodes. One preferred AlGaAs diode array,manufactured by Spectra Physics, Tucson, Ariz., produces a wavelength of980 nm.

Referring back to FIG. 24, waveguide 144 can be coupled to optical fiber142 by various methods known in the art. These methods include forexample, gluing, or fusing with a torch or carbon dioxide laser. In oneembodiment, waveguide 144, optical fiber 142 and, optionally, a gradientindex lens (GRIN) 146 are in communication and are held in position byheat shrinking a polymeric jacket material 149, such as polyethyleneteraphthalate (PET) about the optical apparatus 140.

The optical waveguides, as described in above, can be made frommaterials known in the art such as quartz, fused silica or polymers suchas acrylics. Suitable examples of acrylics include acrylates,polyacrylic acid (PAA) and esters, methacrylates, and polymethacrylicacid (PMA) and esters. Representative examples of polyacrylic estersinclude polymethylacrylate (PMA), polyethylacrylate andpolypropylacrylate. Representative examples of polymethacrylic estersinclude polymethylmethacrylate (PMMA), polyethylmethacrylate andpolypropylmethacrylate. In one preferred embodiment, the waveguide 44 isformed of quartz and fused to the end face of fiber 42.

Internal shaping of the waveguide can be accomplished by removing aportion of material from a unitary body, e.g., a cylinder or rod.Methods known in the art can be utilized to modify waveguide to havetapered inner walls, e.g., by grinding, milling, ablating, etc. In oneapproach, a hollow polymeric cylinder, e.g., a tube, is heated so thatthe proximal end collapses and fuses together, forming an integralproximal portion which tapers to the distal end of the waveguide. Inanother approach, the conical surface 45 can be formed in a solid quartzcylinder or rod by drilling with a tapered bore.

A variety of other energy emitters can be used with the presentinvention, such as those discussed below. FIG. 25 is a schematicillustration of another embodiment of a radiant energy emitter 140Baccording to the invention in which optical fiber 142 is coupled to alight diffuser 141 having light scattering particles 147 to produce asidewise cylindrical exposure pattern of ablative radiation. Thisembodiment can be useful, for example, in creating a lesion within apulmonary vein. With reference again to FIG. 21, it should be clear thatthe radiant energy emitter of the design shown in FIG. 25 can beadvanced to the front of the projection balloon to permit diffuseexposure of a pulmonary vein ostium if a lesion is desired in thatlocation. For further details on the construction of light diffusingelements, see U.S. Pat. No. 5,908,415 issued to Sinofsky on Jun. 1,1999, herein incorporated by reference.

FIG. 26 illustrates an alternative embodiment of a radiant energyemitter 140C in which an ultrasound transducer 160 includes individualshaped transducer elements (and/or lenses or reflectors) 162 whichdirect (project) the ultrasound energy into a cone of energy that canlikewise form an annular exposure pattern upon impingement with a targetsurface. The emitter 140C is supported by a sheath 166 or similarelongate body, that can, for example, enclose electrical leads, therebypermitting the clinician to advance the emitter through an inner lumenof the instrument to a desired position for ultrasound emission.

Yet another embodiment of a radiant energy emitter 140D is illustratedin FIG. 27 where microwave energy is similarly focused into an annularexposure beam. As shown in FIG. 27, the radiant energy emitter 140D caninclude a coaxial transmission line 174 (or similar electrical signalleads) and a helical coil antenna 173. Radiation reflectors 172A and172B cooperated to shield and direct the radiation into a cone. In otherembodiments, a radioisotope or other source of ionizing radiation can beused in lieu of the microwave antenna 173, again with appropriateradiation shielding elements 172A and 172B to project a beam of ionizingradiation.

FIGS. 28 and 29 illustrate one embodiment of a sensor incorporated intoa radiant emitter assembly (such as those discussed above). As shown theassembly includes an assembly body 132 that encases an endoscope/ablatorassembly and facilitates slidable positioning within an inner lumen ofcatheter body 114. The assembly further includes an energy emitter 140(e.g., like those described above) as well as a reference sensor 176. Inuse, if the ablative element 140 of the invention is properly positionedwithin the heart, the ablative element 140 can act as an illuminationlight source such that light transmitted via such ablation element 140will strike the target region, be reflected back, and detected by thereflectance sensor 176. While FIGS. 28 and 29 illustrate one ablativeelement 140 and one reflectance sensor 176, it should be clear that theinvention can be practiced with various numbers of illuminating and/orsensing elements, e.g., two ablative elements and two reflectancesensors, as well as with or without use of the energy emitter as anelement in the contact sensing module. The emitter and the endoscope caneach move independently, if desired. Moreover, ultrasound emitters anddetectors can also be used in the same manner in lieu of the lightreflecting mechanisms to determine contact. In any event, the outputsignals of the sensors can be electronically processed and incorporatedinto a display.

The devices of the present invention can further include illuminationelements that are capable of diffusing light to a large contact area oftissue by employing a scattering medium at the distal end of theillumination fiber. Any diffusing material can be used that allows highintensity light to be uniformly diffused over a large area (preferablyover an area greater than 40 mm in diameter), such as, a matrix oftitanium dioxide particles suspended in cured silicone.

Referring back to FIG. 28, endoscope 176, can include an optical fiberbundle 178 for transmitting the captured image back to a detector anddisplay, as well as a lenses 236 and 240 which provide an enhanced fieldof view. Such field enhancing elements preferably increase the field ofview to greater than 50°, more preferably to about 70° or higher.Typically, commercially available endoscopes have a field of view ofabout 50° or less in air. However, when immersed in water or similarfluids, the field of view of the endoscope is further reduced due to therefractive index difference between water and air. As explained in moredetail below, a greater field of view is very important to endoscopicguidance.

One skilled in the art will appreciate that the endoscopes of FIGS. 28and 29 provide the ability to position the percutaneous ablationinstruments of the present invention at a treatment site such thatproper location of the energy emitter vis-à-vis the target tissue (aswell a satisfactory degree of contact between the projection balloon andthe tissue) is achieved.

The endoscopes of the present invention can also be used in conjunctionwith other optical reflectance measurements of light scattered orabsorbed by blood, body fluids and tissue. For example, white lightprojected by an illumination source toward tissue has several componentsincluding red and green light. Red light has a wavelength range of about600 to about 700 nanometers (nm) and green light has a wavelength rangeof about 500 to about 600 nm. When the projected light encounters bloodor body fluids, most if not all green light is absorbed and hence verylittle green or blue light will be reflected back toward the opticalassembly which includes a reflected light collector. As the apparatus ispositioned such that blood and body fluids are removed from thetreatment field cleared by an inflated balloon member, the reflectanceof green and blue light increases as biological tissue tends to reflectmore green light. As a consequence, the amount of reflected green orblue light determines whether there is blood between the apparatus andthe tissue or not.

Thus, the endoscopic displays of the present invention can incorporatefilters (or generate “false-color” images) that emphasize the presenceor absence of blood in the field. For example, when the inflated balloonmember contacts the heart tissue (or is close enough that the balloonand ablative fluid released by the instrument form a clear transmissionpathway), more green light will be reflected back into the opticalassembly and the collector. The ratio of two or more differentwavelengths can be used to enhance the image. Accordingly, acolor-enhanced endoscope permit visualization of the instrument and/orthe target site, as well as a determination of whether blood precludesthe formation of a continuous lesion, e.g., circumferential lesionaround the ostium of a pulmonary vein.

Alternatively, spectrographic measurements can be taken in tandem withendoscopic imaging, Thus, reflected light can be transmitted backthrough a collector, such as an optical fiber to a spectrophotometer.The spectrophotometer (such as spectrophotometer model S-2000 from OceanOptics Spectrometer, Dunedin, Florida) produces a spectrum for eachreflected pulse of reflected light. Commercially available software(LabView Software, Austin, Tex.) can isolate values for specific colorsand perform ratio analyses.

Once the operator is satisfied with the positioning of the instrument,radiant energy can then be projected to the target tissue region. If theradiant energy is electromagnetic radiation, e.g., laser radiation, itcan be emitted onto the tissue site via a separate optical fiber or,alternatively, through the same optical fiber used to transmitting thewhite, green or red light. The laser light can be pulsed intermittentlyin synchronous fashion with the positioning/reflecting light to ensurethat the pathway remains clear throughout the procedure.

It should be clear that the imaging and contact sensing aspects of thepresent invention are not limited to radiant energy ablation devices butcan also be useful in placement of contact heating or cooling ablationinstruments as well. For example, in FIG. 30, a contact-heating device254 having an expandable element 256 and a contact heating element 258is shown disposed in a pulmonary vein. The contact heating element 258can be a line or grid of electrically conductive material printed on thesurface of the expandable element 256. In one embodiment, the expandableelement 256 can be substantially opaque to certain wavelengths (e.g.,visible light) except for a transparent band 259, on which the contactheating element is situated. The heating wires should also besufficiently transparent (or cover a substantially small area of theband) so as to not interfere with reflection signal collection. Thedevice 254 can further include a sensor, e.g., an endoscope, disposedwithin a central lumen of the device having an illuminating fiber and aplurality of collecting fibers.

In FIG. 31, another embodiment of a reflectance sensing orendoscope-guided catheter is shown in the form of a cryogenic ablationcatheter 310 having a catheter body 312 and internal conduits 314 forcirculation of a cryogenic fluid from a cryogenic fluid source 315. Thecatheter body 312 can include an expandable portion, e.g., a balloonstructure, and further includes conductive regions 316 where the coldtemperature can be applied to tissue. The endoscope 376 of the presentinvention can be disposed in proximity to the conductive regions, asshown and used to determine whether tissue contact has been made.

FIG. 32 illustrates yet another application for the contact sensors. Asshown, the contact sensor can be used in connection with an ultrasound,contact-heating balloon catheter 420 having a balloon 422 (similar tothose discussed above) for contacting a pulmonary vein ostium and havingan optional band 423 for applying heat to tissue. The ultrasoundablation instrument 420 further includes transducers 424 driven byactuator 425 to heat a desired region of tissue. The instrument 420 canalso include reflectors 426 to project the ultrasound energy through theballoon into an annular focus in the target tissue (or at the surface ofthe balloon). Again, the reflectance or endoscopic sensors 476 of thepresent invention can be disposed within the balloon or catheter body,as shown, and used to determine whether tissue contact has been made.

In FIG. 33, an assembly 432 is shown having a translatory mechanism 480for controlled movement of a radiant energy emitter 440. The translatorymechanism 480 is similar to that discussed above, that is the exemplarytranslatory mechanism 480 is incorporated into a handle 484 in theproximal region of the instrument, where the elongate body 482 of theradiant energy emitter 440 engages a thumb wheel 486 to controladvancement and retraction of the emitter. Moreover, various alternativemechanisms of manual or automated nature can be substituted for theillustrated thumb wheel 486 to position the emitter at a desiredlocation relative to the target tissue region.

The assembly 432 of FIG. 33 can also include additional features. Forexample, the elongate body 482 that supports the ablation instrument canfurther include position indicia 492 on its surface to assist theclinician in placement of the ablation element within the instrument.The handle can further include a window 490 whereby the user can readthe indicia (e.g., gradation markers) to gauge how far the emitter hasbeen advanced into the instrument.

Moreover, the assembly 432 can include an endoscope translatorymechanism 498 for controlled movement of the reflectance sensor orendoscope 476 within the instruments of the present invention. Theexemplary positioner 498 can be incorporated into a handle 499 in theproximal region of the instrument, where the elongate body of the sensor476 engages a thumb wheel 497 to control advancement and retraction ofthe emitter.

In use, the separate branches for both the emitter 440 as well as theendoscope 476 allow the endoscope to be extracted prior to theentry/advancement of the emitter 440 into the target tissue site. Oneskilled in the art will appreciate that this can prevent the endoscope476 from being damaged by the energy from the emitter 440.

One skilled in the art will also appreciate further features andadvantages of the invention based on the above-described embodiments.Accordingly, the invention is not to be limited by what has beenparticularly shown and described, except as indicated by the appendedclaims. All publications and references cited herein are expresslyincorporated herein by reference in their entirety.

1. A deflectable sheath catheter, comprising: an elongate catheter bodyhaving proximal and distal ends; the catheter body comprising aplurality of flexible segments along its length, at least one of thesegments having a different stiffness; and a deflectable distal endsection at the distal end of the catheter body, wherein the segments ofdifferent stiffness permit the deflectable distal end section to form acompound curve upon deflection.
 2. The catheter of claim 1, wherein thecompound curve is a spiral curve.
 3. The catheter of claim 1, whereinthe segments of different stiffness are formed by a plurality polymericsegments of the elongate body having different durometers.
 4. Thecatheter of claim 3, wherein the polymeric segments further comprisePbax polymer.
 5. The catheter of claim 3, where the durometer of thedistal end section decreases in the distal direction along at least aportion of the section.
 6. The catheter of claim 1, wherein the elongatecatheter body comprises at least one braided wire reinforcement layer.7. The catheter of claim 6, wherein the catheter comprises at least onebraided wire cladding surrounding at least a portion of the body length.8. The catheter of claim 6, wherein the reinforcement layer iscontinuous.
 9. The catheter of claim 6, wherein the reinforcement layeris discontinuous.
 10. The catheter of claim 6, wherein the reinforcementlayer is varied to provide segments of different stiffness.
 11. Thecatheter of claim 1, further comprising an actuator that effectsdeflection of the deflectable tip section.
 12. The catheter of claim 11,wherein the actuator further comprises a lock to fix the deflectabledistal end section in a particular curve within its range of movement.13. The catheter of claim 12, wherein the actuator further comprises apull wire mechanically linking the deflectable distal end section to aproximal handle portion.
 14. The catheter of claim 1, wherein thedeflectable tip section has a plurality of flexible segments of varyingstiffness.
 15. The catheter of claim 14, wherein the stiffness of theplurality of segment varies progressive over at least a portion of thedistal end section.
 16. The catheter of claim 1, wherein the deflectabledistal end section includes at least one irrigation port.
 17. Thecatheter of claim 1, wherein the deflectable distal end section includesat least one radioopaque band.
 18. The catheter of claim 1, wherein thehandle comprises at least one hemostasis valve.
 19. The catheter ofclaim 1, wherein the deflectable distal end section further comprises adistal tip that is bent out of a plane of deflection.
 20. A cardiacablation instrument assembly, comprising: a deflectable sheath catheteradapted for disposition within a heart having at least one lumentherein, the catheter having at least one segment of different stiffnessto form a compound curve upon deployment and deflection within theheart; and an ablation instrument movable within a lumen of thedeflectable sheath catheter such that it can be disposed at a targettissue site to deliver ablative energy.
 21. The assembly of claim 20,wherein the ablation instrument is a radiant energy emitter furthercomprising a translatory mechanism for positioning the emitter at aselected location within the deflectable sheath catheter.
 22. Theassembly of claim 21, wherein the radiant energy emitter is selectedfrom the group consisting of ultrasound, hypersound, light, microwaveradiation, radio-frequency (RF) radiation, x-ray radiation, ionizingradiation and particle beam radiation emitters.
 23. The assembly ofclaim 21, wherein the radiant energy emitter is a light emitter.
 24. Theassembly of claim 23, wherein the radiant energy emitter is an infraredlight emitter
 25. The assembly of claim 21, wherein the radiant energyemitter is an ultrasound emitter.
 26. The assembly of claim 21, whereinthe radiant energy emitter is a focused acoustic energy emitter.
 27. Theassembly of claim 20, wherein the ablation instrument is a contactablation instrument.
 28. The assembly of claim 27, wherein the contactablation instrument is selected from the group consisting of cryogenicablation instruments, ablative fluid instruments and heatinginstruments.
 29. The assembly of claim 27, wherein the contact ablationinstrument is a cryogenic ablation instrument.
 30. The assembly of claim27, wherein the contact ablation instrument is an ablative fluidinstrument.